It is proposed to investigate ribosomal preparations from Streptococcus mutans for use in the anti-caries vaccine. Ribosome-enriched fractions will be obtained from strain GS-5 and biochemically analyzed as to content. The material will be injected into rabbits solely, as well as in combination with purified glucosytransferase (GTF) enzymes, and antisera will be characterized for ability to: adhere to and agglutinate serotype c cells, prevent adherence of the bacteria, inhibit GTF activity, react with mammalian tissues and provide cross-serotype of protection. After the nature of the immunogen and antibody response has been determined in rabbits, the ability of the vaccine to prevent dental caries will be tested in rats.